Inflammation-induced shift in the valence of spinal GABA-A receptor-mediated modulation of nociception in the adult rat.

Unlabelled: The objective of this study was to assess the impact of persistent inflammation on spinal gamma-aminobutyric acid-A (GABA-A) receptor-mediated modulation of evoked nociceptive behavior in the adult rat. Nocifensive threshold was assessed with von Frey filaments applied to the dorsal surface of the hind paw. The GABA-A receptor agonist muscimol, the antagonist gabazine, the benzodiazepine receptor agonist midazolam, and antagonists PK11195 and flumazenil were administered spinally in the presence and absence of complete Freund's adjuvant (CFA)-induced inflammation.

A brainstem substrate for analgesia elicited by intraoral sucrose.

Previous studies demonstrated that nursing or intraoral infusion of certain components of mother's milk (e.g. sugars and fats) produces calming and opiate receptor-dependent analgesia in newborn rats and humans.

Alterations in stress-associated behaviors and neurochemical markers in adult rats after neonatal short-lasting local inflammatory insult.

Recently, there has been a growing interest in long-term consequences of neonatal pain because modern neonatal intensive care units routinely employ procedures that cause considerable pain and may be followed by local inflammation and hyperalgesia lasting for several hours or even days. To address this question, we developed a rat model of short lasting (<2 days) early local inflammatory insult produced by a single injection of 0.25% carrageenan (CAR) into the plantar surface of a hindpaw.

Characterization of basal and re-inflammation-associated long-term alteration in pain responsivity following short-lasting neonatal local inflammatory insult.

Recently, several studies have suggested that neonatal noxious insult could alter future responses to painful stimuli. However, the manifestations, mechanisms, and even developmental nature of these alterations remain a matter of controversy. In part, this is due to the lack of detailed information on the neonatal sensitive period(s) during which noxious stimulation influences future nociception, and the time-course and distribution of the resultant abnormalities.

Ontogeny of analgesia elicited by non-nutritive suckling in acute and persistent neonatal rat pain models.

Significant analgesic and calming effects in human infants and neonatal rodents are produced by orogustatory and orotactile stimuli associated with nursing. These naturally occurring analgesic stimuli may help to protect the vulnerable developing nervous system from the long-term effects of neonatal tissue injury. However, the efficacy of orotactile-induced analgesia across the pre-weaning period, as well as its effects on persistent inflammatory pain, is unknown.